Index scheming for filter parameters

Abstract

A method of processing an audio signal is disclosed. According to embodiments of the method, magnitude response information of a prototype filter is determined. The magnitude response information includes a plurality of gain values, at least one of which includes a first gain corresponding to a first frequency. The magnitude response information of the prototype filter is stored. The magnitude response information of the prototype filter at the first frequency is retrieved. Gains are computed for a plurality of control frequencies based on the retrieved magnitude response information of the prototype filter at the first frequency, and the computed gains are applied to the audio signal.

1 . A method comprising:
 determining one or more properties of an environment of a wearable head device;   determining a target magnitude response based on the one or more properties of the environment, the target magnitude response comprising one or more control frequencies and further comprising a target gain corresponding to a control frequency of the one or more control frequencies;   retrieving a filter comprising magnitude response information;   determining an audio signal based on a first portion of the magnitude response information, wherein the first portion is associated with the target gain; and   presenting the audio signal to a user of the wearable head device,   
       wherein the magnitude response information comprises a plurality of gain values including a first gain corresponding to a first frequency. 
     
     
         2 . The method of  claim 1 , further comprising:
 presenting a test signal via the wearable head device;   detecting a response signal via one or more sensors of the wearable head device; and   determining a relationship between the test signal and the response signal,   
       wherein the audio signal is determined further based on the relationship. 
     
     
         3 . The method of  claim 1 , wherein the magnitude response information is associated with a high-shelving equalizer, and wherein the method further comprises:
 scaling the magnitude response information of the high-shelving equalizer, and   shifting the scaled magnitude response information of the high-shelving equalizer along a frequency axis by a predetermined frequency amount.   
     
     
         4 . The method of  claim 1 , wherein the magnitude response information is associated with a low-shelving equalizer, and wherein the method further comprises:
 scaling the magnitude response information of the low-shelving equalizer, and   shifting the scaled magnitude response information of the low-shelving equalizer along a frequency axis by a predetermined frequency amount.   
     
     
         5 . The method of  claim 1 , further comprising:
 determining an index associated with the first frequency;   determining a lookup table index based on the index associated with the first frequency and further based on an output of one or more sensors of the wearable head device; and   accessing a lookup table via the lookup table index to determine the magnitude response information.   
     
     
         6 . The method of  claim 1 , further comprising:
 detecting an action of the user of the wearable head device via one or more sensors of the wearable head device;   determining a parameter associated with the environment of the wearable head device, the parameter based on the detected action;   determining a lookup table index based on the index associated with the first frequency and further based on the output of the one or more sensors; and   accessing a lookup table via the lookup table index to determine the magnitude response information.   
     
     
         7 . A system comprising:
 a wearable head device comprising one or more sensors and one or more speakers; and   one or more processors configured to perform a method comprising:
 determining one or more properties of an environment of the wearable head device; 
 determining a target magnitude response based on the one or more properties of the environment, the target magnitude response comprising one or more control frequencies and further comprising a target gain corresponding to a control frequency of the one or more control frequencies; 
 retrieving a filter comprising magnitude response information; 
 determining an audio signal based on a first portion of the magnitude response information, wherein the first portion is associated with the target gain; and 
 presenting the audio signal to a user of the wearable head device via the one or more speakers, 
   
       wherein the magnitude response information comprises a plurality of gain values including a first gain corresponding to a first frequency. 
     
     
         8 . The system of  claim 7 , wherein the method further comprises:
 presenting a test signal via the one or more speakers;   detecting a response signal via the one or more sensors; and   determining a relationship between the test signal and the response signal,   
       wherein the audio signal is determined further based on the relationship. 
     
     
         9 . The system of  claim 7 , wherein the magnitude response information is associated with a high-shelving equalizer, and wherein the method further comprises:
 scaling the magnitude response information of the high-shelving equalizer, and   shifting the scaled magnitude response information of the high-shelving equalizer along a frequency axis by a predetermined frequency amount.   
     
     
         10 . The system of  claim 7 , wherein the magnitude response information is associated with a low-shelving equalizer, and wherein the method further comprises:
 scaling the magnitude response information of the low-shelving equalizer, and   shifting the scaled magnitude response information of the low-shelving equalizer along a frequency axis by a predetermined frequency amount.   
     
     
         11 . The system of  claim 7 , wherein the method further comprises:
 determining an index associated with the first frequency;   determining a lookup table index based on the index associated with the first frequency and further based on an output of the one or more sensors; and   accessing a lookup table via the lookup table index to determine the magnitude response information.   
     
     
         12 . The system of  claim 7 , wherein the method further comprises:
 detecting an action of the user of the wearable head device via the one or more sensors;   determining a parameter associated with the environment of the wearable head device, the parameter based on the detected action;   determining a lookup table index based on the index associated with the first frequency and further based on the output of the one or more sensors; and   accessing a lookup table via the lookup table index to determine the magnitude response information.   
     
     
         13 . A non-transitory computer-readable medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform a method comprising:
 determining one or more properties of an environment of a wearable head device;   determining a target magnitude response based on the one or more properties of the environment, the target magnitude response comprising one or more control frequencies and further comprising a target gain corresponding to a control frequency of the one or more control frequencies;   retrieving a filter comprising magnitude response information;   determining an audio signal based on a first portion of the magnitude response information, wherein the first portion is associated with the target gain; and   presenting the audio signal to a user of the wearable head device,   
       wherein the magnitude response information comprises a plurality of gain values including a first gain corresponding to a first frequency. 
     
     
         14 . The non-transitory computer-readable medium of  claim 13 , the method further comprising:
 presenting a test signal via the wearable head device;   detecting a response signal via one or more sensors of the wearable head device; and   determining a relationship between the test signal and the response signal,   
       wherein the audio signal is determined further based on the relationship. 
     
     
         15 . The non-transitory computer-readable medium of  claim 13 , wherein the magnitude response information is associated with a high-shelving equalizer, and wherein the method further comprises:
 scaling the magnitude response information of the high-shelving equalizer, and   shifting the scaled magnitude response information of the high-shelving equalizer along a frequency axis by a predetermined frequency amount.   
     
     
         16 . The non-transitory computer-readable medium of  claim 13 , wherein the magnitude response information is associated with a low-shelving equalizer, and wherein the method further comprises:
 scaling the magnitude response information of the low-shelving equalizer, and   shifting the scaled magnitude response information of the low-shelving equalizer along a frequency axis by a predetermined frequency amount.   
     
     
         17 . The non-transitory computer-readable medium of  claim 13 , the method further comprising:
 determining an index associated with the first frequency;   determining a lookup table index based on the index associated with the first frequency and further based on an output of one or more sensors of the wearable head device; and   accessing a lookup table via the lookup table index to determine the magnitude response information.   
     
     
         18 . The non-transitory computer-readable medium of  claim 13 , the method further comprising:
 detecting an action of the user of the wearable head device via one or more sensors of the wearable head device;   determining a parameter associated with the environment of the wearable head device, the parameter based on the detected action;   determining a lookup table index based on the index associated with the first frequency and further based on the output of the one or more sensors; and   accessing a lookup table via the lookup table index to determine the magnitude response information.